/================================================/
DAO(Data Access Object)資料存取物件
主要的功能是資料操作，屬於資料層的操作
client → JSP/Servlet → BO → DAO → Database
客戶層 顯示層 業務層 資料層 資源層
client → B/S開發架構，大都以Browser進行存取
顯示層 → 以JSP/Servlet進行頁面效果的顯示
Business Object→ 將多個最小的DAO進行組合變成一個業務邏輯--> BO
DAO→ 提拱多個最小性的DAO操作，例如新增刪除、修改
/================================================/
DAO → 由以下幾個部分組成：
Database Connection → 負責資料庫的開啟與關閉 (xxx.dbc.DatabaseConnection)
VO → 主要是屬性，setter、getter方法組成，與欄位相對應，每一個VO的組成都對應到一條記錄 (like JavaBean)
DAO → 定義操作的介面，新增、刪除、修改、按ID查詢等 (xxx.dao.ImplDAO)
Impl → DAO介面的真實實歸類別，完成實際的資料庫操作不負責開啟和關閉(xxx.dao.xxxImplDAO)
Proxy → 代理實現類別，完成資料庫的開啟和關閉 (xxx.dao.xxxDAOProxy)
Factory → 工廠類別，透過他取得一個DAO產生的實體物件 (xxx.factor.DAOFactory)
/================================================/
組成: 註冊系統 --> 將資料存到架設好的mySQL建表
1. index.jsp、emp_list.jsp、insert_success.jsp
2. com.demo => DatabaseConnection.java、Emp.java、IEmpDAO.java、IEmpDAOImpl.java、EmpDAOProxy.java、DAOFactory.java
3. com.dome.dbc => DatabaseConnection.java、MySQLDatabaseConnection.java
##ReadMore##
//index.jsp
<%@ page language="java" import="java.util.*" import="java.sql.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>新增員工</title>
</head>
<body bgcolor="silver">
<center>
<h2><font color="blue" size="7">【南臺科大－員工註冊系統】</h2></font>
<form action="insert_success.jsp" method="post" >
<font size="5">●員工編號:</font><input type="text" name="empno"><br>
<font size="5">●員工姓名:</font><input type="text" name="ename"><br>
<font size="5">●員工職位:</font><input type="text" name="job"><br>
<font size="5">●到職日期:</font><input type="text" name="hiredate"><br>
<font size="5">●基本薪資:</font><input type="text" name="sal"><br>
<input type="submit" value="註冊">
<input type="reset" value="重設">
</form>
</center>
</body>
</html>
//insert_success.jsp
<%@ page language="java" import="java.util.*" import="java.util.Date" import="java.sql.*" pageEncoding="UTF-8"%>
<%@ page import="com.demo.*" %>
<%@ page import="java.text.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'insert_success.jsp' starting page</title>
</head>
<% request.setCharacterEncoding("UTF-8"); %>
<body>
<%
Emp emp=new Emp();
emp.setEmpno(Integer.parseInt(request.getParameter("empno")));
emp.setEname(request.getParameter("ename"));
emp.setJob(request.getParameter("job"));
emp.setHiredate(new SimpleDateFormat("yyyy-MM-dd").parse(request.getParameter("hiredate")));
emp.setSal(Float.parseFloat(request.getParameter("sal")));
try{
if(DAOFactory.getIEmpDAOInstance().doCreate(emp)){
%>
<h3>新增成功</h3>
<%
}else{
%>
<h3>新增失敗</h3>
<%
}
%>
<%
}catch(Exception e){
e.printStackTrace();
}
%>
</body>
</html>
//emp_list.jsp
<%@ page language="java" import="java.util.*" pageEncoding="BIG5"%>
<%@ page import="java.util.*,com.demo.*"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'emp_list.jsp' starting page</title>
</head>
<%
request.setCharacterEncoding("UTF-8");
%>
<body>
<%
try {
String keyword = request.getParameter("kw");//接收查詢關鍵字
if (keyword == null) {//判斷是否有傳遞參數
keyword = ""; // 如果沒有查詢關鍵字，則查詢全部
}
List<Emp> all = DAOFactory.getIEmpDAOInstance().findAll(keyword);
Iterator<Emp> iter = all.iterator();//產生實體Iterator物件
%>
<center>
<form action="emp_list.jsp" method="post">
請輸入查詢關鍵字：<input type="text" name="kw"> <input type="submit"
value="查詢">
</form>
<table border="1" width="80%">
<tr>
<td>僱員編號</td>
<td>僱員姓名</td>
<td>僱員工作</td>
<td>僱傭日期</td>
<td>基本薪水</td>
</tr>
<%
while (iter.hasNext()) {
Emp emp = iter.next();
%>
<tr>
<td><%=emp.getEmpno()%></td>
<td><%=emp.getEname()%></td>
<td><%=emp.getJob()%></td>
<td><%=emp.getHiredate()%></td>
<td><%=emp.getSal()%></td>
</tr>
<%
}
%>
</table>
</center>
<%
} catch (Exception e) {
e.printStackTrace();
}
%>
</body>
</html>
//DatabaseConnection.java
package com.demo;
import java.sql.Connection;
import java.sql.DriverManager;
public class DatabaseConnection {
public static final String DBDRIVER="com.mysql.jdbc.Driver";
public static final String DBURL="jdbc:mysql://localhost:3306/people";
public static final String DBUSER="root";
public static final String DBPASSWORD="abc123";
private Connection conn;
public DatabaseConnection()throws Exception{
Class.forName(DBDRIVER);
this.conn=DriverManager.getConnection(DBURL, DBUSER, DBPASSWORD);
}
public Connection getConn(){
return this.conn;
}
public void close() throws Exception{
if(this.conn!=null){
try{
this.conn.close();
}catch(Exception e){
throw e;
}
}
}
}
//Emp.java
package com.demo;
import java.util.Date;
public class Emp {
private int empno;
private String ename;
private String job;
private Date hiredate;
private float sal;
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
public Date getHiredate() {
return hiredate;
}
public void setHiredate(Date hiredate) {
this.hiredate = hiredate;
}
public float getSal() {
return sal;
}
public void setSal(float sal) {
this.sal = sal;
}
}
//IEmpDAO.java
package com.demo;
import java.util.List;
//IEmpDAO.java
//定義DAO操作標準
public interface IEmpDAO {
//doCreate主要執行資料庫的插入操作，操作時要傳入一個Emp物件
public boolean doCreate(Emp emp)throws Exception;
//emp增加的資料物件
//return是否成功
//findAll主要完成資料的查詢操作，因為是查詢的結果，所以使用List傳回
public List findAll(String keyword)throws Exception;
//keyword 查詢關鍵字
//return傳回查詢結果，每一個Emp是一筆記錄
//findById根據員工編號傳回一個Emp物件，其包含一個完整的資料資訊
public Emp findById(int empno)throws Exception;
//empno員工編號
//return員工的VO物件
/*
doCreate()方法執行資料庫插入的操作，執行插入時要傳入一個Emp物件，此物件中有要資加的員工資訊
findAll()主要完成資料的查詢，因為傳回的是多條查詢資訊，所以用List傳回，findById()主要是將Emp
物件的編號傳回。
*/
}
//IEmpDAOImpl.java
package com.demo;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
public class IEmpDAOImpl implements IEmpDAO{
private Connection conn=null;
private PreparedStatement pstmt=null;
public IEmpDAOImpl(Connection conn){
this.conn=conn;
}
public boolean doCreate(Emp emp) throws Exception {
// TODO Auto-generated method stub
boolean flag=false;
String sql="INSERT INTO emp(empno, ename, job, hiredate, sal) VALUES (?,?,?,?,?)";
this.pstmt=this.conn.prepareStatement(sql);
this.pstmt.setInt(1,emp.getEmpno());
this.pstmt.setString(2,emp.getEname());
this.pstmt.setString(3,emp.getJob());
this.pstmt.setDate(4,new java.sql.Date(emp.getHiredate().getTime()));
this.pstmt.setFloat(5,emp.getSal());
if(this.pstmt.executeUpdate() > 0){
flag=true;
}
this.pstmt.close();
return flag;
}
public List findAll(String keyword) throws Exception {
// TODO Auto-generated method stub
//定義和接收全部的資料
Listall=new ArrayList();
String sql="SELECT empno, ename, job, hiredate, sal FROM emp WHERE ename LIKE ? or job LIKE ?";
this.pstmt=this.conn.prepareStatement(sql);
this.pstmt.setString(1,"%"+keyword+"%");
this.pstmt.setString(2,"%"+keyword+"%");
ResultSet rs=this.pstmt.executeQuery();
Emp emp=null;
while(rs.next()){
emp=new Emp();
emp.setEmpno(rs.getInt(1));
emp.setEname(rs.getString(2));
emp.setJob(rs.getString(3));
emp.setHiredate(rs.getDate(4));
emp.setSal(rs.getFloat(5));
all.add(emp);//向集合中增加物件
}
this.pstmt.close();
return all;//傳回所有集合的結果
}
public Emp findById(int empno) throws Exception {
// TODO Auto-generated method stub
Emp emp=null;
String sql="SELECT empno, ename, job, hiredate, sal FROM emp WHERE empno=?";
this.pstmt=this.conn.prepareStatement(sql);
this.pstmt.setInt(1,empno);
ResultSet rs=this.pstmt.executeQuery();
if(rs.next()){
emp=new Emp();
emp.setEmpno(rs.getInt(1));
emp.setEname(rs.getString(2));
emp.setJob(rs.getString(3));
emp.setHiredate(rs.getDate(4));
emp.setSal(rs.getFloat(5));
}
this.pstmt.close();
return emp;//如果查詢不到結果則傳回null,預設為null
}
}
//EmpDAOProxy.java
package com.demo;
import java.util.List;
public class EmpDAOProxy implements IEmpDAO{
private DatabaseConnection dbc=null;
private IEmpDAO dao=null;
public EmpDAOProxy()throws Exception{
this.dbc=new DatabaseConnection();
this.dao=new IEmpDAOImpl(this.dbc.getConn());
}
public boolean doCreate(Emp emp) throws Exception {
// TODO Auto-generated method stub
boolean flag=false;
try{
if(this.dao.findById(emp.getEmpno())==null){
flag=this.dao.doCreate(emp);
}
}catch(Exception e){
throw e;
}
finally{
this.dbc.close();
}
return flag;
}
public List findAll(String keyword) throws Exception {
// TODO Auto-generated method stub
List all=null;
try{
all=this.dao.findAll(keyword);
}catch(Exception e){
throw e;
}
finally{
this.dbc.close();
}
return all;
}
public Emp findById(int empno) throws Exception {
// TODO Auto-generated method stub
Emp emp=null;
try{
emp=this.dao.findById(empno);
}catch(Exception e){
throw e;
}finally{
this.dbc.close();
}
return emp;
}
}
//DatabaseConnection.java
package com.demo.dbc;
import java.sql.Connection;
public interface DatabaseConnection {
public Connection getConnection();
public void close();
}
//MySQLDatabaseConnection.java
package com.demo.dbc;
import java.sql.Connection;
public class MySQLDatabaseConnection implements DatabaseConnection {
public void close() {
// TODO Auto-generated method stub
}
public Connection getConnection() {
// TODO Auto-generated method stub
return null;
}
}
執行結果:
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